The present invention relates to a semiconductor device and a method for producing the same, and a method for mounting a semiconductor device. In particular, the present invention relates to a semiconductor device in the form of a chip that can increase the efficiency of mounting on a wiring substrate, allows high-density mounting, and can realize highly reliable substrate mounting, and a method for producing the same, and a method for mounting a semiconductor device. The present invention also relates to a semiconductor device in which electrode pads for external terminals are rewired on a semiconductor chip, and the external terminals are arranged two-dimensionally and a method for producing the same, and a method for mounting a semiconductor device.
In recent years, high-density mounting of a semiconductor package having a lead terminal as its external terminal has been promoted with the development of light-weighted, compact and high-density portable equipment. Under these circumstances, for higher density mounting, a technique for mounting a semiconductor device in the form of a chip on a wiring substrate of electronic equipment has been developed.
Hereinafter, a conventional semiconductor device that is mounted on a wiring substrate and a method for mounting a semiconductor will be described with reference to the accompanying drawings.
FIG. 9 schematically shows a cross-sectional structure of a conventional semiconductor device, and the semiconductor device shown in FIG. 9 is a semiconductor device in the form of a chip used for bare chip mounting. The semiconductor device includes a semiconductor chip 1 including a semiconductor integrated circuit inside its upper surface, and electrode pads (not shown) electrically connected to the semiconductor integrated circuit are provided on the semiconductor chip 1. Protruded electrodes 2 are formed on the electrode pads (not shown).
The protruded electrodes 2 are formed in the peripheral portion of the semiconductor chip 1 to constitute external terminals for electrical connection to the outside. The protruded electrodes 2 are made of conductive metal protrusion such as bumps and solder balls. Although not shown, an insulating layer is formed on a region excluding the electrode pads on the upper surface of the semiconductor chip 1.
Next, referring to FIGS. 10A to 10C, a conventional method for mounting a semiconductor device will be described.
To mount the semiconductor device as shown in FIG. 9 on a wiring substrate, first, a wiring substrate 3 such as a printed substrate to be incorporated into electronic equipment is prepared. Then, as shown in FIG. 10A, wiring electrodes 4 for connection provided on the upper surface of the wiring substrate 3 are aligned with the protruded electrodes 2 on the principal surface of the semiconductor chip 1 of the semiconductor device.
Then, as shown in FIG. 10B, the wiring electrodes 4 on the wiring substrate 3 are connected to the protruded electrodes 2 on the semiconductor device. In this case, when the protruded electrodes 2 are solder balls, the solder balls are joined to the wiring electrodes 4 on the wiring substrate 3 while the solder balls are melted.
Thereafter, as shown in FIG. 10C, the gap between the semiconductor chip 1 of the semiconductor device and the wiring substrate 3 is filled and sealed with an underfill material 5 such as an insulating resin while the protruded electrodes 2 of the semiconductor device are connected to the wiring substrate 3. Then, the underfill material 5 is cured to finish the substrate mounting.
FIGS. 11A to 11C show another mounting method. In this mounting method, an under filling material is first supplied onto a surface of a wiring substrate, and the semiconductor device is pressed onto the substrate in such a manner that the under filling material is sandwiched for connection. Hereinafter, this approach will be described more specifically.
First, as shown in FIG. 11A, the underfill material 5 as an insulative resin sheet having a desired thickness and area is attached onto the wiring electrodes 4 of the wiring substrate 3 such as a printed substrate to be incorporated into electronic equipment.
Then, as shown in FIG. 11B, the wiring electrodes 4 of the wiring substrate 3 are aligned with the protruded electrodes 2 of the semiconductor, and then the semiconductor device is pressed with its face down under heat and pressure in such a manner that the underfill material 5 as an insulating resin sheet supplied onto the surface of the wiring substrate 3 is sandwiched therebetween, so that the protruded electrodes 2 penetrate the underfill material 5. Thus, the protruded electrodes 2 of the semiconductor chip 1 are connected to the wiring electrodes 4.
Thereafter, as shown in FIG. 11C, the sheet-like underfill material 5 is cured to finish the substrate mounting.
As described above, in the conventional devices, the wiring electrodes on the wiring substrate are connected to the semiconductor device in the form of a chip used for bare chip mounting via the protruded electrodes, and the underfill material is formed in the gap therebetween to mount the semiconductor device, and thus the underfill material is formed by being supplied after or before the connection of the semiconductor device and the wiring electrodes.
The conventional semiconductor device has a structure where the protruded electrodes are provided on electrode pads disposed in the peripheral portion of a semiconductor chip, and the electrode pads are formed in the peripheral region outside the semiconductor integrated circuit element on the semiconductor chip. Therefore, the two-dimensional area arrangement of the electrode pads inside the chip surface cannot be achieved, so that there is a limit for higher density as a semiconductor device.
For this reason, recently, a semiconductor device has been under development in which electrode pads on the semiconductor chip are wired around (rewired), and contact pads connected to the electrode pads in a two-dimensional area are formed on the principal surface (on the semiconductor integrated circuit element) of the semiconductor chip. However, there are various limitations in order to connect such a semiconductor device (that is, a semiconductor device in which contact pads connected to electrode pads are formed on the semiconductor integrated circuit element region) and a wiring substrate.
For example, when performing substrate mounting by supplying a sheet-like or film-like underfill material onto a wiring substrate, and pressing protruded electrodes formed on the contact pads of the semiconductor device with the underfill material sandwiched therebetween, a pressure is applied to the semiconductor device. Consequently, this pressure causes damage to the semiconductor integrated circuit element below the contact pads of the semiconductor device, which imposes some limitations on how to mount it on a substrate. Furthermore, when connecting the wiring electrodes on the wiring substrate to the contact pads, and then filling and sealing the gap between them with an underfill material, voids may be generated in the underfill material.
Furthermore, in the conventional method for mounting a semiconductor device, it is necessary to fill or attach an underfill material to a wiring substrate for each semiconductor device to achieve substrate mounting, which causes a problem in terms of the mounting efficiency of substrate mounting. In addition, there is also an increase in the mounting cost due to the introduction of a new mounting facility with high precision for use in substrate mounting.
Therefore, with the foregoing in mind, it is a main object of the present invention to provide a semiconductor device and a mounting method that can improve the mounting efficiency of substrate mounting. It is another object of the present invention to provide a semiconductor device that can realize highly reliable substrate mounting and a method for producing the same, and a method for mounting a semiconductor device.
A semiconductor device of the present invention includes a semiconductor chip having a principal surface provided with a plurality of electrode pads; an insulating layer formed on a region excluding the plurality of electrode pads on the principal surface of the semiconductor chip; a plurality of contact pads arranged on the insulating layer on the principal surface of the semiconductor chip; a wiring layer electrically connected to at least one of the plurality of electrode pads and electrically connected to at least one of the plurality of contact pads, thereby establishing rewiring connection; an insulative resin layer formed on a region excluding the plurality of contact pads on the principal surface of the semiconductor chip; a protruded electrode provided on each of the plurality of contact pads; and an underfill material layer provided on the insulative resin layer in such a manner that the top of the protruded electrode is exposed.
Another semiconductor device of the present invention includes a semiconductor chip having a principal surface provided with a plurality of electrode pads; an elastic layer formed on a region excluding the plurality of electrode pads on the principal surface of the semiconductor chip; a plurality of contact pads arranged two-dimensionally on the elastic layer on the principal surface of the semiconductor chip; a wiring layer electrically connected to at least one of the plurality of electrode pads and electrically connected to at least one of the plurality of contact pads, thereby establishing rewiring connection; an insulative resin layer formed on a region excluding the plurality of contact pads on the principal surface of the semiconductor chip; a protruded electrode provided on each of the plurality of contact pads; and an underfill material layer provided on the insulative resin layer in such a manner that the top of the protruded electrode is exposed.
In one embodiment of the present invention, the upper surface of the underfill material layer is substantially flush with the top of the protruded electrode.
In one embodiment of the present invention, the top of the protruded electrode is projected and exposed from the upper surface of the underfill material layer by 1 xcexcm to 200 xcexcm.
In one embodiment of the present invention, the protruded electrode is a solder ball.
It is preferable that the protruded electrode is a solder ball, and the underfill material layer is made of a thermoplastic resin.
It is preferable that the Young""s modulus of the elastic layer is 10 to 2000 kg/mm2.
In one embodiment of the present invention, the underfill material layer is an epoxy resin layer.
It is preferable that the end of the elastic layer has an oblique side in its cross section.
A method for producing a semiconductor of the present invention includes preparing a semiconductor chip having a principal surface provided with a plurality of electrode pads; forming an elastic layer made of a low elastic material on a region excluding the plurality of electrode pads on the principal surface of the semiconductor chip; forming a wiring layer having one end electrically connected to at least one of the plurality of electrode pads, and having the other end extended onto the elastic layer to arrange contact pads two-dimensionally; forming an insulative resin layer for coating at least the wiring layer and the electrode pads, except the plurality of contact pads, on the principal surface of the semiconductor chip; forming a protruded electrode made of a conductive material provided on the contact pad; and forming an underfill material layer on the principal surface of the semiconductor chip in such a manner that the top of the protruded electrode is exposed.
It is preferable that the step of preparing a semiconductor chip is the step of preparing a semiconductor water in which a plurality of semiconductor chips are formed on its surface.
A mounting method of the present invention is for mounting a semiconductor device on a substrate with electrical connection between the semiconductor device and the wiring substrate having wiring electrodes. The semiconductor device includes a semiconductor chip having a principal surface provided with a plurality of electrode pads; an elastic layer formed on a region excluding the plurality of electrode pads on the principal surface of the semiconductor chip; a plurality of contact pads arranged two-dimensionally on the elastic layer on the principal surface of the semiconductor chip; a wiring layer electrically connected to at least one of the plurality of electrode pads and electrically connected to at least one of the plurality of contact pads, thereby establishing rewiring connection; an insulative resin layer formed on a region excluding the plurality of contact pads on the principal surface of the semiconductor chip; a protruded electrode provided on each of the plurality of contact pad; and an underfill material layer provided on the insulative resin layer in such a manner that the top of the protruded electrode is exposed. The method includes opposing the principal surface of the semiconductor device to the principal surface of the wiring substrate to align the protruded electrode of the semiconductor device with the wiring electrode on the wiring substrate; bringing the protruded electrode of the semiconductor device into contact with the wiring electrode on the wiring substrate; and softening and melting the underfill material layer of the semiconductor device by heating to fill and seal the gap between the principal surface of the semiconductor device and the principal surface of the wiring substrate with the underfill material layer.
In one embodiment of the present invention, the step of bringing the protruded electrode of the semiconductor device into contact with the wiring electrode on the wiring substrate is performed by pressing the top of the protruded electrode exposed from the underfill material layer into the wiring electrode on the wiring substrate by applying a pressure for contact with each other.
In one embodiment of the present invention, the top of the protruded electrode included in the semiconductor device is projected and exposed from the upper surface of the underfill material layer, the protruded electrode is a solder ball, and the underfill material layer is made of a thermoplastic resin, and the method further includes applying a solder paste having a melting point lower than the melting point of the solder ball onto the wiring electrode on the wiring substrate; and melting the applied solder paste at a temperature lower than the melting point of the solder ball after the protruded electrode is in contact with the wiring electrode.
According to the present invention, the underfill material layer is formed on an insulative resin layer in such a manner that the tops of the protruded electrodes are exposed, so that the mounting efficiency of substrate mounting can be improved. Moreover, highly efficient and highly reliable substrate mounting can be realized by bringing the semiconductor device having the underfill material layer into contact with the wiring electrodes on the wiring substrate and heating the underfill material.
The method for producing a semiconductor device of the present invention allows the elastic layers, the wiring layers and the underfill material layers in a large number of semiconductor chip regions to be formed in a semiconductor water that has not been divided into semiconductor chips. Therefore, it is possible to reduce the production cost significantly by preparing semiconductor chips for use in production in the form of a semiconductor wafer.
In addition, in the structure in which the protruded electrodes included in the semiconductor device are formed with solder balls, and the tops thereof are projected and exposed from the upper surface of the underfill material layer made of a thermoplastic resin, the self-aligning function can be exerted effectively, if a solder paste having a melting point lower than the melting point of the solder balls is provided on the wiring electrodes on the wiring substrate, and then the protruded electrodes and the wiring electrodes are brought into contact, and then, the solder paste is melted at a temperature lower than the melting point of the solder balls.